Pump for pumping through a variable volume plunger chamber having a pair of plungers disposed in a stepped cylinder with a slide valve

ABSTRACT

A pump for pumping through a variable plunger chamber having a pair of plungers disposed in a stepped cylinder with a slide valve includes two plungers of different diameters, united to each other. As they move within a stepped cylinder, the plungers form a chamber of variable volume according to the ratio of their height in respect of the step formed by the cylinder. The ports and clearance between the stem and the plunger chamber create intake, by means of the port housed in the plunger chamber on driving the stem in its upward stroke, and drive by means of the port drilled in the stem on forcing the stem in its downward stroke. Just three structural components are needed for operation of the pump.

FIELD OF THE INVENTION

This invention relates to the technical field of hydraulics.

BACKGROUND OF THE INVENTION

Pumps are classified according to the movement of the force body of thepump, such as:

1) piston pumps, wherein the drive piston has a reciprocatingstraight-line movement;

2) rotary pumps, wherein the drive piston has a reciprocating angularmovement; and

3) centrifugal pumps, wherein the body turns inside the pump body.

The following are descriptions of the prior art types of piston pumps:

Single acting pumps: on the upward stroke, it lifts by opening theintake valve, which is housed in the cylindrical valve inlet. On thedownward stroke, it closes this valve and, in turn, opens the deliveryvalve through which it discharges the volume of the contents of thecylinder.

Valve piston pumps: the delivery valve is mounted on the plunger, whichhas openings. The plunger thereby forms two chambers in the cylindricalbody, intake taking place in the lower chamber, and compression takingplace in the upper chamber when the plunger rises.

Tubular piston pumps: the plunger consists of a tube carrying thedelivery valve actuated by a rod on its outside.

Double-acting pumps: made by joining two single-acting pumps.

Horizontal plunger pumps: consist of a plunger shared by two pumps. Oneach stroke, one side of the plunger lifts while the other compresses.

Differential pumps with horizontal and vertical plunger: on the upwardstroke of the plunger, intake and injection into the delivery tube takeplace at the same time. On the downward stroke, the lower side of theplunger causes an injection through a union tube into the uppercylindrical space. However, the plunger stem also displaces fluids whichpass to the delivery tube. Therefore, the pump works through intake andcompression on the upward stroke, and on the downward stroke bycompression only.

The components of conventional piston pumps are:

Cylinder

Piston

Piston drive stem

Intake valve casing box with its valve

Delivery valve box with its valve.

SUMMARY OF THE INVENTION

A pump for pumping through a variable volume plunger chamber having apair of plungers disposed in a stepped cylinder with a slide valveincludes two plungers of different diameters united to a single stem andhousing in a cylinder. On the plunger-stroke, a difference of volumesoccurs. Pumping is achieved through intake and drive by means of valveswhich direct the flow in only one direction. The pumping is not theresult of piston displacement, but the volume loss in the cylinder dueto its variable diameter.

The two plungers shifted by a single rod on each stroke in a cylinder oftwo different diameters create a chamber of variable diameter whichcauses the displacement of fluids.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical section view of the pump in the position ofpressure on the stem.

FIG. 2 is a vertical sectional view of the pump in the intake position.

FIG. 3 is a perspective and sectional view of the plunger chamber.

FIG. 4 is a vertical sectional view of the pump in its metering version,in the intake position.

FIG. 5 is a vertical sectional view of the pump in its metering version,in the drive position.

FIG. 6 shows a diagram of the plastic parts required for the executionof a current metering pump.

FIG. 7 is a vertical sectional view showing a specimen embodiment ofthis invention as a cosmetic product metering pump.

FIGS. 8 and 9 are vertical sectional views of the embodiment of theinvention using diaphragms.

FIGS. 10 and 11 are vertical sectional views of the pumps in positionsshown in FIGS. 2 and 1, respectively.

FIG. 12 is a vertical sectional view showing an embodiment of thisinvention by means of a hollow stem with two diaphragms.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The pump includes an intake pipe 2 and a hollow stem 3, surrounded atits lower end by a plunger chamber 4, so that when the pump body 1 andthe intake tube 2 are filled with air (FIGS. 1,11) the hollow stem 3rises, on its upward travel it draws the plunger chamber 4, the liquidthen follows an upper plunger 4A in its ascent, and pump intake takesplace. The amount of liquid which enters into the pump body is equal tothe product of the plunger action due to its travel. When the hollowstem 3 moves down, that is during drive, it causes the plunger chamber 4to descend, and the plungers 4A, 4B inject the amount of thedifferential volume between the cylinders 5A, 5B into the delivery pipe3A.

On each drive the fluid level into the delivery pipe 3A rises until itreaches the draining opening.

The pump body 1 has two stages of different diameters, cylinders 5A, 5Bonce the pump body 1 and the delivery pipe 3A are full of liquid; ateach stroke a quantity of liquid equal to the difference in thecapacities formed by the two different diameters, both of the plungers4A, 4B and of the cylinders 5A, 5B, enters into the cylinder formedbetween the plungers 4A, 4B, and at each drive stroke the same amount ofliquid enters into the delivery pipe 3A.

The plunger chamber 4 on the upper plunger 4A has a stop 3B so that,when the pump is positioned vertically, pressing the stem 3 draws theplunger chamber 4 in its descent by means of the stop 3B, closing at thesame time its intake port 4C (FIG. 3), and opening the delivery port 3Cdrilled in the stem 3, by which the fluids are discharged.

As shown in FIGS. 2,10 once the downstroke is completed, the stem 3 isno longer pressed so that the stem 3, helped by a spring, begins itsupward stroke, drawing the plunger body. Because of the clearancebetween the stem 3, stops 3B, 3D will cause the plugging of the deliveryport 3C and opening of the port 4C in the plunger chamber 4 whereby thefluids will begin to enter the variable diameter cylinder 5A, 5B. Thiscauses the pumping of the volumetric difference between the cylinders5A, 5B to take place.

As shown in FIG. 3, the plunger chamber is provided with a plug 4H toplug the lower end of the stem.

On this pump, the following elements have been replaced:

Intake valve box with its valve

Delivery valve box with its valve These elements have been replacedwith:

An intake port, located in the lower plunger 4B

A delivery port 3C, drilled in the stem 3

These two ports are opened and closed by means of the clearances in thedisplacements of the stem 3 and plunger chamber 4.

Therefore only three component parts are needed to attain pumping:

cylinders 5A, 5B,

plunger chamber 4, and

stem 3.

By the use of plastic-injection molding each part can be produced insingle units. On assembly of the pump only these three component partsand the return spring are required. A total of four fabricated piecesfor full operation, for example, of a metering pump for cosmeticsproducts (FIG. 7), consisting of:

A stem 3 incorporating a delivery port 3C the liquid outlet head beingintegrated into this part and the stem's bottom aperture being pluggedby the cylinder integrated into the part that forms the plunger chamber4.

A plunger chamber 4 with its intake port and integral cylinder to sealthe lower opening of the stem.

A variable diameter chamber 1, including an adjusting cap with themetering device.

A return spring.

A metering pump is therefore achieved by the utilization of only fourcomponents. FIGS. 4 and 5 show the metering pump in intake and drivepositions. FIG. 6 shows the plastic components necessary for thefabrication of an actual metering pump, with the addition of the returnspring. The seating of the intake valve 1B can be integrated in thechamber 1. For the valve 1B, an enclosing cone or sphere is used.Another component is the plunger situated on the plunger-rod, where adelivery port 4 has been drilled. This port is opened and closed by theclearance between the stem 3 and the plunger 4. The fluid outlet headcannot be built into the stem 3, because in the plastic-injectionmolding process the aperture at the bottom of the stem 3 could not beplugged to prevent the reflux of fluid forced into the pump chamber. Theadjusting cap 5 with the liquid reservoir are included in the stem 3locating guide. It can be seen that six integral pieces are necessaryfor a metering pump. There are other types in existence, which need morethan six pieces, utilizing tubular plungers. It can therefore beobserved that the variable volume plunger chamber metering pump is thatwhich requires least fabricated components. It can also work in anyposition, without needing any elements which press on or maintain valvesin their seating.

In another embodiment illustrated by FIGS. 8 and 9, two diaphragms 2A,2B of different diameters attached to the same stem 3 are housed in acylinder 4 in the stroke of which the diameters of the diaphragms 2A, 2Bare included half and half. On the upstroke of the stems, the upperdiaphragm 2A assisted by its lower stops 3A allow the diaphragm 2A toremain taut and flush with the cylinder 4 surface, creating a vacuum onthe upward stroke, which raises the ends of the lower diaphragm 2Bthrough atmospheric pressure. A displacement of fluids takes place, intothe volume formed between the underside of the upper diaphragm 2A andthe top side of the lower diaphragm 2B. On the downstroke, the liquidinside the pump chamber puts pressure on the diaphragms 2A, 2B, whileputting less pressure on the stops 3B and the cylinder wall 4, therebypreventing the escape of liquid over its edges. The upper diaphragm 2Aflexes under the resultant pressure and the liquid is forced over thelip of the diaphragm 2A into the upper cavity of the cylinder. Throughthis process, the pumping action is achieved.

FIG. 12 shows the hollow stem 3, with the upper and lower diaphragms 2A,2B. The stem 3 is bored above the upper diaphragm, to thereby forcefluids through the stem 3 due to the action of the retaining plunger 3Flocated above the port 3C in the stem 3. Stops 3B, 3D prevent flexing ofthe upper and lower diaphragms 2A, 2B.

I claim:
 1. A pump for pumping through a variable volume plunger chambercomprising: a stepped cylinder having a first chamber having acomparatively large diameter and a second chamber having a comparativelysmall diameter;an upper plunger having a comparatively large diameterand a lower plunger having a comparatively small diameter, said plungersbeing united to each other and moving through the stepped cylinder; ahollow stem slideable inside the stepped cylinder for plugging a firstport drilled in the smaller diameter plunger, while at the same timeuncovering a second port in the hollow stem which was previously sealedby the larger diameter plunger, whereby fluids are forced through thesecond port as volume of the larger diameter chamber decreases and, whenthe stroke is completed, the hollow stem rises leaving the first portopen, while at the same time closing the second port.
 2. The pumpaccording to claim 1 wherein an inlet valve is located in the lowerplunger.
 3. A pump for pumping through a variable volume plunger chambercomprising a pair of plungers of different diameters disposed in astepped cylinder having a slide valve, the pair of plungers comprisingan upper and a lower plunger formed as a single component; and,the slidevalve comprising a hollow stem slidable inside the variable volumeplunger chamber for plugging a first port drilled in the lower plunger,while at the same time uncovering a second port in the hollow stem whichwas previously sealed by the upper plunger, whereby fluids are forcedthrough the second port as volume in the chamber changes and, when thestroke is completed, the hollow stem rises leaving the first port open,while at the same time closing the second port.
 4. The pump according toclaim 3 wherein an inlet valve is located in the lower plunger.
 5. Apump for pumping through a variable volume plunger chamber comprising anupper plunger and a lower plunger disposed in a stepped cylinder havinga slide valve, the pump including two diaphragms attached to a stem, thediaphragms having different diameters and being housed in a cylinderhaving bottom stop; and,the slide valve comprising a hollow stemslidable inside the variable volume plunger chamber for plugging a firstport drilled in the lower plunger, while at the same time uncovering asecond port in the hollow stem which was previously sealed by the upperplunger, whereby fluids are forced through the second port as volume inthe chamber changes and, when the stroke is completed, the hollow stemrises leaving the first port open, while at the same time closing thesecond port.